题解 | #二叉树的最大深度#

'''
https://www.nowcoder.com/practice/8a2b2bf6c19b4f23a9bdb9b233eefa73?tpId=196&&tqId=37055&rp=1&ru=/activity/oj&qru=/ta/job-code-total/question-ranking
'''
# -*- coding:utf-8 -*-
class TreeNode:
    def __init__(self, x):
        self.val = x
        self.left = None
        self.right = None

# @param root TreeNode类 
# @return int整型
#
class Solution:
    def maxDepth(self , root ):
        # write code here

        if not root:
            return 0

        out = []
        def dfs(root,res):
            if not root:
                return
            if not root.left and not root.right:
                out.append(res)
            if root.left:
                dfs(root.left, res+[root.left.val])
            if root.right:
                dfs(root.right, res+[root.right.val])

        dfs(root,[root.val])

        depth = 0
        for i in out:
            if len(i)>depth:
                depth = len(i)

        return depth